Art of blasting



(No Model.)

J. A. KURTZ. ART OP BLASTING.

nnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnnn cA Patented July 8, 1890! i"UNITED STATES PATENT OFFICE.v

JOHN A. KURTZ, OF PITTSBURG, PENNSYLVANIA.

ART OF BLASTING..

'SPECIFICATION forming part of Letters Patent No. 431,747, dated July 8,1890.

Application filed October 2, 1889. Serial No. 325,784. (No model.)

To all whom it .may concern:

Be it known that I, JOHN A. KURTZ, a resident of Pittsburg, in thecounty of Allegheny and State of Pennsylvania, have invented certain newand useful Improvements in the Art of Blasting and I do hereby declarethe following to be a full, clear, and exact description of theinvention, such as will enable others skilled in the art to which itpertains to make and use the same.

The object of the invention is to simplify and cheapen methods of anddevices for blasting rock heretofore employed, and particularly thosemethods the purpose of which has been to direct the force of explosionin such manner as to produce fracture along predetermined lines. Onemethod of this has been to drill a circular hole in the rock, as usual,and then to forni grooves continuous with the hole and along the linesin which it was desired to split the rock. This mode increases the laborof drilling and requires special tools for the purpose. This eXtra laborand the use of such particular tools is avoided by my invention, whichconsists in the matter hereinafter set forth and particularly pointedout.

In the accompanying drawings, Figure l is a central section in verticalplane on line X X of Fig. 2 of a charge partition and tamping located ina bore in rock. Fig. 2 is an enlarged transverse sect-ion of the same online Y Y, the bore in the rock being indicated by the circle. Figs. 3,4, and 5 are similar views of modifications of the partition. Fig. 6 isa partial vertical section in a plane through the longest diameter of apartition, showing location of fuse in the partition; Fig. 7, a likeView showing means for introducing the partition. Fig. 8 is atransversesection showing another form of partition or bar, and Fig. 9 is across-section of a bar made in two parts to provide for the readyinsertion of fuse.

The figure of reference l indicates a rod, bar, or strip of anyconvenient materialsuch as wood or iron-placed in' a drill-hole of usualform in a manner to act as a partition and divide the charge 2 ofexploding material. Said dividing-bar has its edges 3 near or in actualcontact with the surface of the rock. This partition may be firstinserted and the powdersubsequently charged 5 or the partition may beforced down through the powder previously introduced, the foot of thepartition having been suitably sharpened for u this purpose.

At 6 in the bottom of the bore, and below the powder, is indicated asmall quantity of dirt or like material, which is employed for thepurpose of preventing the dividing-bar from being thrown out by theexplosion. It tends to exclude the expanding gases from passing downbelow the bar and acting against its post in a vertical direction.

The form of the partitions may be varied. A few of the possiblemodifications are indicated in the drawings. They may be maderectangular in cross-section, or their several faces, the number ofwhich can be two, three, or more, may be made either convex or concave.Their function isto divide the explosive and to direct the force ofexplosion in such manner as to fracture the rock-bed in planes passingthrough the edges of the partition. These edges may be in actual contactwith the face of the bore or may be removed a slight distance andsufiiciently to permit ignition between the edge of the partition andthe rock.

Figs. 2, 3, and 5 illustrate dividing bars or partitions, having eachtwo edges or lines of contiguity with the face of the bore, and Fig.1.1. exhibits four such lines or edges.

In Fig. 6 is shown a fuse, passing dow-n through the bore in adividing-bar. It can be introduced, however, in any convenient manner.For example, a slot may first be made in the bar which will admit thefuse sidewise,

which slot can be closed outside the fuse by a piece of material fittedtherein; or the partition can be made in two parts, one or both of whichis suitably grooved to receive the fuse, as indicated in Fig. 6, andthese may be yfastened together in any convenient manner.

In case the partition extends to the top of the bore, or above it, asindicated in Fig. 6, a cap or washer 4C may be secured upon it withinthe bore in the rock to sustain the tamping.

In Fig. 7 is illustrated means for introducing a short bar or partition.In its upper end isahole, provided with suitable screw-threads orequivalent, to receive a rod 5, correspond- IOO ingly threaded. Thisrod, being connected with the bar, can be used to lower it in the holein the rock either before or after the powder and -fuse have beenintroduced. A washer can be used to hold the partition centrally andsupport the tamping, or paper may be rammed in for this purpose. Beforetamping, the rod is unscrewed and removed, and the top of the partitionthen receives the main force of the blows employed in this part of theoperation. IVhen the explosive, the fuse, or equivalent igniter, and thepartition have been properly placed in the bore, the charge will bedivided into two or more portions by the bar 1, the edges of said barbein g arranged in the planes of desired fracture. Thereupon the chargeis ignited, and I have discovered that its explosive force is sodirected and expended by the above-described means as to break the rockin planes, passing through the edges of the dividing-bar about midwaybetween the adjoining faces of the bar. The bar being acted uponsimultaneously by the separate divisions of the exploding material,causes the force of explosion to react in opposite directions or indirections determined by the faces of the bar. The novelty and utilityof the invention, however, does not depend upon the above explanation ortheory, as the suggested result can be attained by proceeding asspecified, whatever theory may be entertained, and thereby the labor andvexpense of grooving the bore along the desired line of fractureheretofore incurred can be obvia'ted; noris it essential that the edgesof the bar be vertically arranged, as similar effects can be produced byarranging them horizontally or in planes between the vertical and thehorizontal, or even in curved lines.

It will be understood that neither the use of the dirt packing at thebottom of the bore, nor the particular time or order of inserting theexplosive, nor the special means of introducing the dividing-bar, northe particular form or-number of such bars, nor the inode of tampingareessential to the main effect of my improvement. According to thepreferred method, however, a dirt packing sufficient to cover the footof the bar is first introduced and the bar is then inserted and forcedinto the dirt, whereupon the explosive material is charged and the fuseor other ignitor inserted in manner to insure ignition of the wholecharge, and, finally, suitable material is tamped about and upon the topof the bar and the charge exploded.

In Fig. S I have shown the simplest means for carrying out my improvedmethod, which consists in a bar entered in the blast-hole, and adaptedto produce with the wall of said hole anzelongated opening,which may beapproximately elliptical or of equivalent form in cross-section, thepurpose of this being to direct the main force of expansion at rightangles to the longest diameter of the bore or hole.

Having thus described my invention, what I desire to secure by Let-tersPatent isl. The improvement in the art of blasting,

which consists in providing a cylindrical bore or charging-hole and individing the charge lengthwise of the bore by a partition, substantiallyas described.

2. The improvement in the art of' blasting, which consists in providinga cylindrical bore or charging-hole and in dividing the chargelengthwise of' the bore by a partition, and placing a packing of dirt orsimilar material about the foot of the partition, substantially asdescribed.

'3. The improvement in the art of blasting, which consists in providinga cylindrical bore or charge hole and dividing the charge lengthwise ofsaid blast hole by a bar or partition having angular or approxi matelyangular edges contiguous to the face of Ithe bore and then exploding thecharge, substantially as described.

4. The improvement in blasting,which consists in forming a cylindricalhole in the material to be blasted, and then partially filling said holelaterally with a bar disposed lengthwise of the cylindrical hole andproducing a charging space or receptacle having an approximately oblongform, substantially as described.

In testimony whereof I have signed this specification in the presence oftwo subscribing witnesses.

JOHN A. KURTZ.

Vitnesses:

J oHN H. CRATTY, WILLIAM RAPF.

